1. Field of the Invention
The present invention relates to a fuel tank connector, in particular a connector capable of effectively decreasing leakage of evaporative emissions from a fuel tank.
2. Discussion of Background
As shown in FIGS. 23 and 24, a fuel tank 100 usually has a pipe 101, such as a fuel feeding pipe and a pipe for guiding gas generating from the fuel, connected thereto. The connection of the pipe 101 is made by use of a connector 110 fitted to the fuel tank 100 as shown in FIGS. 23 and 24.
The connector 110, which is shown in FIGS. 23 and 24, includes a tubular portion 111 for connection with the pipe 101, a flanged portion 112 projecting laterally from a peripheral portion of one end of the tubular portion 111 melt-bonded to the tank 100 so as to cover an opening 100a in the tank 100, and a fuel cutoff valve 113 provided in the flanged portion 112 on a side opposite the tubular portion 111. The tubular portion 111 and the flanged portion 112 are integrally molded from high-density polyethylene.
The fuel cutoff valve 113 in the shown connector 110 includes a float chamber forming box 113b formed in a cylindrical shape, having a valve seat unit 113a with a valve seat 113a′ at the opening of a bore in communication with a bore in the tubular portion 111, having a bottom opened and made of polyacetal; a float 113c having an upper portion integrally formed with a valve 113e and housed in the box 113b so as to be slidable therein; and a lid 113d closing the opened bottom of the box 113b and cooperating with the box to form the float chamber with the float 113c incorporated therein. As the float 113c rises, the valve 113e makes close contact with the valve seat 113a′ to close the opening.
In the connector 110, the box 113b of the fuel cutoff valve 113 is configured to be integrally fitted to the flanged portion 112 so as to have an upper side of the box 113b embedded in the flanged portion 112 by, e.g., plastic molding wherein the box is integrally united to the flanged portion with the box being inserted in a mold. A peripheral portion of the flanged portion 112 with the box 113b is melt-bonded to a surface of the tank 100 around the opening 100a of the tank 100 with the box 113b being inserted into the tank 100 through the opening 100a of the tank 100.
In the connector 110 thus configured, the flanged portion 112 and the tubular portion 111 are made of high-density polyethylene. The evaporative emissions generating from the fuel in the tank 100 or another member have been predicted to leak out, though at a regulated value or less, through a portion of the flanged portion 112 provided between an edge of the opening 100a of the tank and the box 113b of the connector 110 melt-bonded to the tank 100.